Clip connector terminal for insulated conductors



April 23, 1968 G. KRONE ET AL 3,380,013

CLIP CONNECTOR TERMINAL FOR INSULATED CONDUCTORS Filed Jan. 14, 1966 INVENTORS GUSTAV KRDNE BY HORST FORBERG ATT .EY

United States Patent ABSTRACT OF THE DISCLOSURE A connector device which comprises a support, a pair of parallel spaced clips disposed in the support; each clip is provided with a slot that is in registry with the other at its upper end but diverges downwardly with respect to one another, a pusher slide adapted to be inserted in said support and force an insulated electric wire that extends through the registering portions of said slots, downwardly, whereby the edges of the diverging slots cut through the insulation and establish an elec trical connection with said wire; said pusher slide locks with said clips in its fully inserted positon.

This invention relates to a clip connector for establishing a quick electric connection between an insulated conductor and a metallic connector member.

It is known in the art to use clip connector devices which comprise an insulated support, a pair of parallel disposed clip members provided with opposed slots which at their upper end are provided with registering enlargements and the width of which is slightly smaller than the diameter of the aforesaid metallic conductor.

In order to establish an electric connection of the type mentioned above, the insulated conductor is placed into the registering enlargements of both slots and is sub sequently pushed into the slots in a direction normal to the axis of the conductor. As the insulated conductor advances within the slots, the sharp edges thereof push aside or cut through the insulation and slidingly bite into the conductor, scraping away any oXide layer that may surround the conductor and establishing a good electric connection between the conductor and the clip members.

By pushing the insulated conductor from the enlargements into the slots, the edges thereof, due to their resiliency, yield slightly and separate so as to engage the scored conductor with a resilient force.

By using clip connector terminals of this known type it is no longer necessary to strip the insulation from the conductor prior to making a connection. Thus, considerable time is saved especially in installations comprising electric equipments having a great plurality of conductors and terminals (e.g. distributors for telephone lines). Conductors having a plastic insulation are particularly well adapted since such insulation may be easily cut through.

An object of the invention is to provide an improved clip connector terminal of the type set forth hereinabove wherein the electric resistance between the conductor and the metallic connector member of the clip is permanently at a very low value even under unfavorable operating circumstances.

A further object of the invention is to provide a clip connector terminal of the type set forth hereinabove wherein the elastic characteristics between the edges of the slots and the conductor are improved to the extent that even in the case of a slight flow of the normally soft conductor material in the region of the contact no substantial slackening of the contact pressure will occur.

Still another object of the invention is to provide an improved clip connector terminal of the type set forth hereinabove that is adapted to relieve the conductor portions engaged in the clip slots from external tensioning and bending forces without making the connecting operation between the conductor and the metallic connector member more difficult or more complicated.

A further object of the invention is to provide an improved clip connector terminal of the type set forth hereinabove wherein the sectional dimensions of the terminal clip connectors are such that a large number of the connectors may be built into a compact unit to form a single, elongated terminal strip.

Further objects and advantages will become apparent from the ensuing detailed specification taken in conjunction with the drawing wherein:

FIG. 1 is a substantially enlarged front elevational view of one embodiment of the invention shown partially in section;

FIG. 1a is a substantially enlarged front elevational view of a pusher member forming part of the embodiment;

FIG. 2 is a sectional view along lines 22 of FIG 1;

FIG. 2a is a side elevational view of FIG. 1a;

FIG. 3 is a view similar to FIG. 2 showing the pusher member in an inserted and locked position; and

FIG. 4 is a sectional view along line 44 of FIG. 3.

Referring now to FIG. 1 there is shown, by way of example, a terminal strip 10 comprising a clip support 11 having the shape of an elongated rail and provided with a plurality of serially arranged chambers 12 of rectangular cross-section. It is noted that FIG. 1 merely shows one broken-off end of a terminal strip 10 containing three chambers 12. The entire elongated support may contain as many chambers in series as the number of insulated conductors in a multi-lead cable with which the terminal strip 10 is to be associated. The chambers 12 open upwardly and are provided at their base 13 with U-shaped guiding slots 14 which extend through the socket portion 15 of the support 11 parallel with the axis of chambers 12. These guiding slots 14 function as holders for the elongated solder strips 16 of U-sh-aped cross-section which are inserted into the chamber 12 from above and which form part of the connector members 17.

Each connector member 17 is made of a resilient, relatively thin metal sheet and comprises within the chamber 12 two opposed face-to-face arranged clip members 18a and 18b in which there is cut or stamped a clip slot 19a and 19b, respectively. The width of the slots is smaller than the diameter of the metallic conductor to be inserted for reasons that will become apparent as the specification progresses. Each slot 19a and 19b is enlarged to form registering enlargements or apertures 20a and 2012. As seen in FIG. 2, an electric conductor 21 is arranged to pass through the registering enlargements 20a and 20b prior to its insertion into the slots 19a and 19b.

The front and the rear walls of the support 11 are provided at the middle of each chamber 12 with a cutout 22 having an arcuate base. These cutouts extend from the upper edge of the support walls below the lower end of the slots 19a and 19b.

As seen in FIG. 1 the slots 19a and 19b (viewed from the front) are disposed at an angle to one another so that their lower ends are laterally displaced and are thus spaced from each other at a somewhat greater distance than their upper ends adjacent the apertures 20a, 20b. Expressed in other terms, the center lines of both slots are arranged in a skewed manner in relation to one another. The slots 19:: and 1912, thus so arranged, the clips 18a and 18b may be of identical configuration and may be arranged parallel to one another.

Due to the skewed arrangement of slots 19a and 1%, the metallic conductor 21a of the insulated wire 21 will be tensioned between the two resilient clips as it is being pushed into the two slots. Also, the conductor 21a will be slightly drawn through at least one of the slots thereby causing, at the slot edges, a comparison or accumulation of the surface material in an axial direction. Further, as the conductor is forced into the slots, the clips will be resiliently deflected along the longitudinal dimension of the wire. Thus, between the wire and the clips there exists not only a deforming and contact pressure against the wire radially thereof caused by the resilient expansion of the slots, but also there appears an axial deforming and contact pressure created by a larger elastic deflection of the clips with respect to one another. The spring action of the clips normal to their plane compensates for the cold flow of the relatively soft conductor material and maintains a contact pressure of large value at the places of contact so that the electrical resistance of the contacting portions does not substantially increase even after long use under unfavorable operating conditions.

As seen in FIG. the two clips 18a and 1812 are bent at their upper portions with respect to each other in such a manner that the distance therebetween, at the joint of enlargements 20a and 20b with the slots 19a and 19b, is smaller than the distance between the lower end of slots 1% and 1%. In this manner second means is provided to render the distance between the upper ends of the slots 19a and 1% smaller than that of the lower ends. The kink lines closest to one another on the two clips 13a and 18b are designated at 23 in FIGS. 1 and 2. With this arrangement of the two clips it would be possible to arrange the slots in such a manner that their center lines lie in the vertical symmetry plane of the clips and still achieve the axial tensioning effect referred to hereinabove. Thus, viewing it from the front, the slots would not be at an angle with respect to one another as shown in FIG. 1 but would be in registry throughout their length.

The embodiment shows both axial tensioning means in combination, although it would be within the scope of the invention to use only one means for improving the resilient characteristics at the locations of contact. The result of either solution is that the distance between each opposed point of an imaginary centerline of the two slots gradually increases in a downward direction.

Below the slots 19a and 1% there are provided in each clip opposed and inwardly extending protrusions 24 below which there are formed tongues 25 disposed in registry and spaced from each other at a distance smaller than the distance of any other part of the two clips 18a and 18b.

Protrusions 24 function as locking members for the pusher to be described hereinbelow. The protrusions 24 do not extend to the outer edges of clips 18a and 18b; the outer edges are held in narrow lateral grooves (not shown) provided in the separating walls 26 of chambers As seen in FIGS. la and 2a, each clip connector is associated with a pusher slide 30 used to force at least one insulated conductor 21 into the slots Ma and 19b. The pusher slide 3% comprises a head portion 31, an intermediate portion 32, a pair of opposed, downwardly extending, spaced, laterally disposed pusher arms 33a and 33b and a central pusher portion 34 which at its lower end terminates in a forked member 35 that func tions as a locking means once the pusher slide is inserted in position. The width of arms 33a, 33b corresponds to that of cutouts 22.

The entire pusher 30 is made of a slightly resilient plastic such as polyamid. The central pusher portion 34 of pusher slide 30 is adapted to be inserted between clips 18a and 18b and is further adapted to exert a pressure to that portion of conductor 21 that lies between clips 18a and 185. As the pusher St! is inserted, its laterally disposed pusher arms 33a and 33b penetrate into two opposite cutouts 22 of support 11 and exert a pressure on those portions of conductor 21 that lie adjacent to but externally of clips lSti and 18/).

Each of the two forked portions 35a and 35b of pusher slide 30 comprises a projecting perimetral strip 36 which is provided with two pairs of oppositely disposed knobs 37 and 38 (see FIG. 2a) which cooperate with inwardly directed protrusions 24 of clips 18m and 18b. The vertical distance between each knob 37 and 38 substantially corresponds to the outer diameter of the insulated conductor 21 which is to be used in connection with this device.

The lower ends of the lateral pusher arms 33a and 3312, as well as the lower end of the central pusher portion 34 between the forks 35a and 3512, are provided with an aligned arcuate pusher face It).

The terminal strip described hereinabove is used in the following manner:

With the pusher slide 36 removed, an insulated conductor 21 is threaded through cutouts 22 and enlargements or apertures 20a and 2012 as shown in FIG. 2. Subsequently, the pusher slide 3th is positioned into the support 11 over the conductor 21 in such a manner that both forks 35a and 35b straddle the conductor 21 and penetrate into the space between the two clips 18a and 18b. At the same time the lateral pusher arms 33a and 331) are received in cutouts 22. The lower ends of forks 35a, 35b slide past the tongues 25 of clips 18a and 18b while the arcuate pusher faces 39 of both lateral pusher arms 33a and 33b engage the two portions of the insulated conductor 21 which is immediately adjacent to and externally of clips 13a and 1812. On the other hand, the arcuate pusher face 39 of the central pusher portion 34 engages that portion of the conductor which lies between the two clips 13a and 18b.

By pushing the pusher slide 38 farther down into the support 11 it urges the insulated conductor 21 into the skewed slots 19a and 1% whereby the edges of these slots cut through the insulation of the wire and also penetrate to a slight extent into the metallic conductor 21a. By pushing the conductor 21a farther down in slots 19a, 1912 it is exposed to a longitudinal tension between the clips 18a and 18b as it assumes its final position shown in FIGS. 3 and 4. The aforementioned tensioning of the wire 21a occurs for the reason that the distance between the slots 19a and 19b gradually increases in a downward direction. As explained hereinbefore, this increase is caused by either or both of two features: (1) the skewed arrangement of the slots 19a and 1912 as seen in FIG. 2, and (2) the non-parallel arrangement of clips 18a, 18b as seen in FIG. 2. The portions of conductor 21 lying externally of clips 18a and 18b are firmly urged towards the base of the cutouts 22 by lateral pusher arms 33a and 3315. At the same time the locking knobs 37 and 38 pass between the oppositely arranged, inwardly-directed protrusions 24 causing the strip 36 to be compressed and subsequently, as the knobs 38 clear the protrusions 24, the strip expands outwardly causing the locking knobs 38 to assume their looking position under protrusions 24. As seen in FIG. 3, in this final position the conductor 21 is firmly squeezed between the base portions of cutouts 22 and the arcuate pusher faces 39 of the lateral pusher arms 33a and 33b. As a consequence, any tensioning or bending force exerted on the external portions of the conductor may not extend to that portion of the conductor that lies betwen the slots 19a and 1912. Further, as explained hereinbefore, after cutting through the insulation, the portions of the conductor 21 lying between the clips 18a and 18b are tensioned as the clips 18a and 18b resiliently approach each other. During the relative motion between the conductor 21a and the edges of slots 19a and 191), a particularly good cleaning effect of the conductor surface is obtained due to the aforementioned axial shift of the surface layer of the conductor. The resilient deformation of the clips, in addition to the deformation of each slot, ensures that the contacting surfaces are maintained under a continuous resilient pressure which in turn ensures a good electric contact between the conductor and the clip for a long period of operation.

In the event two conductors are to be inserted into a single clip, it is preferred to insert the first wire as previously described, then remove the pusher slide 30, and introduce the second conductor into enlargements 20a and 2012. Finally, the second conductor is then pushed in place by means of the pusher slide 30, at which time, however, only the lower pair of locking knobs 37 engages the lower side of protrusions 24. In this position the two wires lie superimposed between the pusher face 39 and the base portion of cutouts 22.

For an easy removal of pusher slide 311 from support 11, there is provided a means defining an aperture 40 through head portion 31. The means defining the aperture 40 is adapted to receive a hooked portion of a pulling tool for a quick and forceful removal of pusher 30.

The terminal strip 10, described in detail as an exemplary embodiment of the invention, may be inserted into an elongated opening in the end wall of a cable terminal, such as used, for example, in connection with multi-lead telephone cables. The terminal strip is inserted in such a manner that thesoldering terminals 16 extend inwardly towards the leads, while the clip terminals extend outwardly. Thus, the terminal leads of the cable may be soldered to extensions 16, while external conductors may be attached to the terminal clip connectors as described hereinbefore.

It will be understood that it is within the scope of the invention to provide a terminal clip connector compris ing a single clip assembly instead of the undetermined number of clips shown in the described embodiment.

Although only one embodiment of the invention has been depicted and described, it will be apparent that this embodiment is illustrative in nature and that a number of modifications in the apparatus and variations in its end use may be effected without departing from the spirit or scope of the invention as defined in the appended claims.

What is claimed is:

1. A connector device for establishing a quick electrical connection with an electric conductor surrounded by insulation comprising, a support having at least one chamber open at one end, a connector member inserted in said chamber, said member including a pair of faceto-face disposed spaced conductive resilient clips, each clip being provided with a registering aperture adapted to receive said conductor prior to the establishment of said electric connection, a slot extendnig downwardly from each of said apertures, said slot having edges spaced at a distance less than the diameter of said conductor and adapted to cut through said insulation and bite into said conductor, a pusher slide adapted to be inserted into said chamber to urge said conductor transversally of its longitudinal dimension into said slots, said pusher slide includes a central pusher portion adapted to engage said insulated conductor between said clips, a pair of parallel, downwardly extending pusher arms adapted to engage said insulated wire adjacent and externally of said clips and locking means adapted to interengage said clips beyond said slots to maintain said pusher slide in its fully inserted position, the distance between the imaginary centerline of the two slots gradually increasing downwardly from said apertures causing a tensioning force to be imparted by said clips to said conductor as it is being urged downwardly in said slots by said pusher slide.

2. A..connector device as defined in claim 1, wherein said slots are arranged in a skewed relation to one another.

3. A connector device as defined in claim 1, wherein said clips are so arranged with respect to one another that the distance between said clips measured along one slot gradually increases in the direction of advancement of said conductor in said slots.

4. A connector device as defined in claim 1, wherein said support is provided with aligned, downwardly extending cutouts having a base and adapted to receive said pusher arms, said conductor being firmly urged against the base of each cutout by said pusher arms when said pusher slide is in its fully inserted and locked position.

5. A connector device as defined in claim 1, wherein said locking means includes a forked member adapted to straddle said conductor between said clips upon insertion of said pusher slide into said support, diametrically opposed locking knobs disposed on said forks, said clips being provided with a pair of inwardly extending opposed protrusions beyond the end of said slots distal from said apertures, said locking knobs adapted to pass beyond said protrusions and assume a locking position therewith when said pusher slide is in its fully inserted position.

References Cited UNITED STATES PATENTS 1,536,281 5/1925 'Batcheller 339- 2,738,479 3/1956 Gibson 339-98 3,239,796 3/1966 Buchanan et a1. 339-97 FOREIGN PATENTS 71,217 10/1959 France.

MARVIN A. CHAMPION, Primary Examiner.

J. H. MCGLYNN, Assistant Examiner. 

